1. Field of the Invention
The present invention relates to an in-line film deposition system for sequentially transferring substrates to a plurality of vacuum chambers that are arranged along a substrate transfer path, and for carrying out film deposition on these substrates.
2. Description of Related Art
An in-line film deposition system that includes a plurality of vacuum chambers arranged along a linear transfer path has been used as a film deposition system for large-scale production.
FIG. 9 is a schematic plan view of a conventional in-line film deposition system. The in-line film deposition system shown in FIG. 9 comprises a plurality of vacuum chambers 2' arranged along a transfer path 30'. The substrates are positioned in a carrier 3' and transferred by a transfer system, not shown, to vacuum chambers 2' along the transfer path 30'. Processing means 4' are provided in each vacuum chamber 2' for performing film deposition processing.
A plurality of vacuum chambers 2', each of which is enclosed within a rectangular parallelepiped vacuum container 20', are arranged along the linear transfer path 30'. In the upstream and downstream walls of each of the vacuum containers 20' along the transfer path 30' are openings through which the substrate is passed. These openings are provided with gate valves 21'.
Processing means 4' are provided in side walls of the vacuum containers 20', which are parallel to the transfer direction. For film deposition by sputtering, the processing means 41' is provided with a cathode mechanism having a target. Such processing means 4' are generally disposed in a plurality of vacuum chambers 2' to carry out a plurality of film deposition processing procedures on the substrate. Such a plurality of film deposition processing procedures are suitable for the deposition of a multi-layer film comprising a plurality of layers, and for preliminary processing such as heating and cleaning of the substrate.
"Film deposition processing" cited in this specification includes not only literal "film deposition" processing but also other processing which is carried out before and after "film deposition".
The vacuum chamber 2' which is provided the furthest upstream along the transfer path 30' is used as an auxiliary chamber for loading the substrate. The vacuum chamber 2' that is provided the furthest downstream is used as an auxiliary chamber for unloading the substrate. The substrate is held on the carrier 3' and is sequentially transferred to respective vacuum chambers 2' through the gate valves 21'. Specified steps of film deposition processing are carried out in sequence on the surface of the substrate by the processing means disposed in each vacuum chamber 2'.
The conventional in-line film deposition system as described above and illustrated in FIG. 9 is advantageous in that the substrate is not exposed to the air between processing steps and a high quality thin film can therefore be deposited on the substrate.
However, the conventional in-line film deposition system as described above is disadvantageous in that the system is excessively long since the vacuum chambers 2' are arranged in a straight line. Accordingly, the floor space that is occupied by the system in a clean room becomes excessively large. In addition, in the case of the conventional in-line film deposition system, the auxiliary chamber for loading the substrate is located distant from the auxiliary chamber for unloading the substrate. Accordingly, the load-unload operations for the substrate cannot be carried out at one position in the system.